Classic biphasic pulmonary blastoma with endobronchial invasion in a 16-year-old male: A rare case report

Abstract

Pulmonary blastoma (PB) is a rare and aggressive lung neoplasm, representing 0.25 %-0.50 % of lung cancers and characterized by biphasic histology with both epithelial and mesenchymal components. We report a case of a 16-year-old male non-smoker presenting with hemoptysis and a 2-month history of dry cough and exertional dyspnea. Imaging revealed an ill-defined density in the left lung, and bronchoscopy identified a budding mass in the left bronchus. Biopsy results showed malignant spindle cells, with immunohistochemical staining positive for cytokeratin, vimentin, and TTF1, confirming classic biphasic pulmonary blastoma (CBPB). Further CT scans indicated multiple metastases in the right lung and bones. The patient was referred for palliative chemotherapy due to the tumor's aggressive nature. This case highlights the clinical presentation and diagnostic challenges of PB with endobronchial invasion.

Keywords: Classic biphasic pulmonary blastoma; Endobronchial; Lung tumor; Non‐small cell lung carcinomas; Pulmonary blastoma; Sarcomatoid carcinomas.

Fig. 1

CT scan shows a circular density in the upper lobe of the left lung with calcification within it.

Fig. 2

Bronchoscopy shows a polypoid intraluminal mass in the left primary bronchi, 5 cm after the carina.

Fig. 3

Microscopic examination of the bronchial biopsy reveals neoplastic proliferation composed of anaplastic spindle cells with large, irregular and hyperchromatic nuclei with atypical mitoses.

Fig. 4

Microscopic examination of the tru-cut biopsies from the left pulmonary mass. Positive immunohistochemical staining results (CK, Vimentin, TTF1) of the tumoral proliferation formed by tubular fetal structures lined by pseudostratified epithelium associated with mesenchymal component with chondroid and osseous differentiation.

Fig. 5

Contrasted enhanced CT scan of the thorax and abdomen shows a large-sized and lobulated mass with ill-defined margins and high and heterogeneous density containing small calcifications within it, extending to the pulmonary hilum causing obstruction of the left main bronchus and abutting the pulmonary artery, with left-sided pleural effusion. Along with multiple metastases to the right lung and the bones. CT scan, with star marked on it, shows atelectasis in the left lung.